Laminated foam product and methods for making laminated foam products

ABSTRACT

Thermally laminated foam boards, methods for making thermally laminated foam boards, apparatus for making thermally laminated foam boards, smaller foam pieces made from thermally laminated foam boards, methods for making smaller foam pieces from thermally laminated foam boards, parts made from thermally laminated foam boards, methods for making parts from thermally laminated foam boards, and tools for making parts from thermally laminated foam boards are disclosed. The thermally laminated foam boards are made by thermally bonding at least two polystyrene boards together.

RELATED APPLICATIONS

The present application claims the benefit of provisional patentapplication No. 61/650,248, filed May 22, 2012, titled “Foam BoardLaminator and Method for Laminating Foam Boards” which is incorporatedherein by reference.

BACKGROUND

The present invention relates to polymeric rigid foam boards. It findsparticular application in conjunction with polymeric rigid foam boardshaving a broad thickness range produced using a thermo-laminatingprocess and will be described with particular reference thereto. It willbe appreciated, however, that the invention is also amenable to otherapplications.

Engineered extruded polystyrene (XPS) foams have been proven useful inbuilding insulation, and many construction applications. For example,XPS pipe fabrication foam billets are relatively dust free and providethermal and moisture resistance as well as large format foam tooperators for low-temperature cold processes. These engineered XPSapplications usually need large format foam to be fabricated, howeverthe extruded foam boards are limited in the thickness in conventionalprocesses, such as less than 300 mm (˜12″), or more likely less than 120mm (˜5″). It is difficult to extrude thicker products due to manyengineering and operational obstacles (e.g., large die lip gaps that areneeded in operation, which make it difficult to hold die pressure).

The present invention provides a new and improved apparatus and methodfor making relatively thicker XPS foam boards and foam products madefrom the thicker XPS foam boards.

SUMMARY

The present application discloses several different embodiments ofthermally laminated foam boards, methods for making thermally laminatedfoam boards, apparatus for making thermally laminated foam boards,smaller foam pieces made from thermally laminated foam boards, methodsfor making smaller foam pieces from thermally laminated foam boards,parts made from thermally laminated foam boards, methods for makingparts from thermally laminated foam boards, and tools for making partsfrom thermally laminated foam boards. In one exemplary embodiment, afoam product is made by thermally bonding at least two extrudedpolystyrene boards together to make a thick laminated board. The thicklaminated board is machined to remove a portion of the extrudedpolystyrene and thereby form the foam product. The removed polystyreneis recycled.

In one exemplary embodiment, a foam product includes at least twoextruded polystyrene boards bonded together two make a thick laminatedboard. A portion of the extruded polystyrene board is removed to form ashape of the foam product. The formed foam product consists of materialof the polystyrene boards.

In one exemplary method of making a foam product, heat and pressure areapplied to facing surfaces of a pair of opposed extruded polystyreneboards to flatten the facing surfaces by a factor of at least 2. Thepair of extruded polystyrene boards are thermally bonded together tomake a thick laminated board. The thick laminated board is machined toremove a portion of the extruded polystyrene and thereby form the foamproduct.

In one exemplary embodiment, a laminated foam board includes first andsecond extruded polystyrene boards each having an outer skin that isformed during extrusion of the polystyrene boards. The polystyreneboards are laminated together without removing the outer skin of facesthat are bonded together. A bond area between each of the polystyreneboards is substantially planar and has a bond thickness variation ofless than 0.020 inches.

In one exemplary method of making a foam product comprising at least twoextruded polystyrene boards are bonded together to make a thicklaminated board. The thick laminated boards are cut into smaller foampieces. The smaller foam pieces are machined to remove a portion of theextruded polystyrene and thereby form the foam product. A profiletolerance where the smaller foam piece is machined across a thermal bondline between extruded polystyrene boards is less than or equal to 0.015inches from one side of the bond line to the other.

In one exemplary embodiment, a rotary cutting tool for shaping foamproducts includes an annular support, cutting elements, and a base. Theannular support is formed from sheetmetal. Cutting elements are securedto the sheetmetal annular support. A base is secured to the sheetmetalannular support for rotating the sheetmetal annular support and attachedcutting elements.

In one embodiment, a system for laminating foam boards includes awaiting frame, a foam board laminator, and a receiving frame. The foamboard laminator includes a heating frame and an adhering frame. Theheating frame includes a heating element for heating a plurality of foamboards. The adhering frame includes a mechanism for applying pressure tothe heated foam boards for laminating the foam boards together. Thewaiting frame positions the boards at an entrance of the heating frame,and the receiving frame receives the boards from an exit of the adheringframe.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings which are incorporated in and constitute apart of the specification, embodiments of the invention are illustrated,which, together with a general description of the invention given above,and the detailed description given below, serve to exemplify theembodiments of this invention.

FIG. 1 is an illustration of an exemplary embodiment of an extrudedpolystyrene board;

FIG. 2 is a sectional view of the extruded polystyrene board taken alongthe plane indicated lines 2-2 in FIG. 1;

FIG. 2A illustrates that the thickness range may be determined bymeasuring the thickness of the board at various points along the surfaceof the board;

FIG. 3 illustrates a first polystyrene board stacked on top of a secondpolystyrene board;

FIG. 4 is a Figure taken from U.S. Pat. No. 4,608,103;

FIG. 4A is a Figure taken from U.S. Pat. No. 4,608,103;

FIG. 4B is a Figure taken from U.S. Pat. No. 4,608,103;

FIG. 5 is a schematic illustration of an individual foam board that hasbeen separated from a laminated foam board according to the methodillustrated by FIGS. 4, 4A, and 4B;

FIG. 6 is a sectional view taken along the plane indicated by lines 6-6in FIG. 5;

FIG. 7 is a schematic illustration of an exemplary embodiment of anapparatus for flattening a major surface of a foam board;

FIG. 8 is a schematic illustration of an exemplary embodiment of a foamboard having a flattened major surface;

FIG. 9 illustrates an exemplary embodiment of a first foam board stackedon top of a second foam board with flattened major facing surfaces;

FIG. 10 is a flowchart that illustrates an exemplary embodiment of amethod of making a laminated foam board.

FIG. 11 is a schematic illustration of an exemplary embodiment of anapparatus for simultaneously flattening a opposing major surfaces of apair of foam boards;

FIG. 12 is a schematic illustration of an exemplary embodiment of anapparatus for pressing the foam boards illustrated by FIG. 11 togetherto form a laminated foam board;

FIG. 13 is a sectional view of an exemplary embodiment of a laminatedfoam board made by the apparatuses illustrated by FIGS. 11 and 12;

FIG. 14 is an enlarged portion of an exemplary embodiment of a bond lineof the laminated foam board as indicated by reference FIG. 14 in FIG.13;

FIG. 14A is a sectional view of an exemplary embodiment of a laminatedfoam board illustrating a method of measuring variations of a bond area;

FIG. 15 is a schematic illustration of an exemplary embodiment of anapparatus for simultaneously flattening a opposing major surfaces of afoam board and a laminated foam board;

FIG. 16 is a schematic illustration of an exemplary embodiment of anapparatus for pressing the foam board and the laminated foam boardillustrated by FIG. 16 together to form a three layer laminated foamboard;

FIG. 17 is a sectional view of an exemplary embodiment of a laminatedfoam board made by the apparatuses illustrated by FIGS. 15 and 16;

FIG. 18 is a schematic illustration of an exemplary embodiment of anapparatus for flattening opposing surfaces of a pair of foam boards andpressing the foam boards together;

FIG. 19 is a schematic illustration of an exemplary embodiment of anapparatus for making laminated foam boards;

FIG. 20 is a schematic illustration of another exemplary embodiment ofan apparatus for making laminated foam boards;

FIG. 21 is an exemplary methodology for laminating foam boards inaccordance with one embodiment illustrating principles of the presentinvention;

FIG. 22 illustrates a top view of an exemplary embodiment of analternate means for passing foam boards through a heating frame inaccordance with one embodiment illustrating principles of the presentinvention;

FIG. 23 is a schematic illustration of another exemplary embodiment ofan apparatus for making laminated foam boards;

FIG. 23A is a schematic illustration of foam boards passing by heatingrods in accordance with one embodiment of an apparatus illustratingprinciples of the present invention;

FIG. 23B is a schematic representation of foam boards passing by heatingrods in accordance with another embodiment of an apparatus illustratingprinciples of the present invention;

FIG. 24 illustrates an exemplary embodiment of a billet made from alaminated board made in accordance with an exemplary embodiment of thepresent invention;

FIG. 25A illustrates an exemplary embodiment of a tool for making foamproducts out of foam;

FIG. 25B illustrates an exemplary embodiment of a tool for making foamproducts out of foam;

FIG. 26 is a schematic illustration of tools positioned relative to alaminated foam piece;

FIG. 27 is a schematic illustration of a laminated foam piece after afirst cutting operation with a tool;

FIG. 28 is a schematic illustration of a laminated foam piece after asecond cutting operation with a tool;

FIG. 29 is a schematic illustration of a foam product that is formedafter a third cutting operation with a tool;

FIG. 30 is a perspective view of an exemplary embodiment of a foamproduct formed from a laminated foam piece;

FIG. 31 schematically illustrates forming a foam product and recyclingfoam material that is removed during forming of the foam product to makea new foam board;

FIG. 32 is a plan view of an exemplary embodiment of a piece of flatsheetmetal;

FIG. 33 is a side view of the flat piece of sheetmetal illustrated byFIG. 32;

FIG. 34 is a sectional view of an exemplary embodiment of a sheetmetalannular support of a foam cutting tool;

FIG. 35 is a sectional view that illustrates the sheetmetal annularsupport assembled with an exemplary embodiment of a base;

FIG. 36 is a top view of an exemplary embodiment of a plurality ofcutting elements adhered to a bonding material strip;

FIG. 37 is a side view of the plurality of cutting elements adhered tothe bonding material strip illustrated by FIG. 36; and

FIG. 38 is a sectional view of an exemplary embodiment of a rotarycutting tool for shaping foam products.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENT

FIG. 1 illustrates an exemplary embodiment of a foam board 110, such asan extruded polystyrene board. The foam board may be made from a widevariety of different materials. For example, the foam boards 110 can bemade from a wide variety of different thermoplastic materials. In oneexemplary embodiment, the foam board 110 is a polystyrene foam board,such as an extruded polystyrene foam board or an expanded polystyrenefoam board. The illustrated foam board 110 is rectangular with first andsecond major face surfaces 112, 114, spaced apart by a thickness t. Thefoam board 110 has side edges 116, 118, 120, 122 that extend between thefirst and second major surfaces 112, 114. Both of the major surfaces112, 114 may comprise a skin 124 that is formed during the extrusionprocess. The extrusion skin 124 is a stratum of polystyrene materialthat is denser than the interior foamed portion 126 of the board. Thatis, the thin extrusion skin is substantially solid whereas the foamedportion 126 comprises expanded foam cells. Examples of suitable foamboards 110 include the FOAMULAR® Extruded Polystyrene Insulationproducts that are available from Owens Corning.

In one embodiment, it is contemplated that the foam boards 110 areengineered extruded polystyrene (XPS) foams having a molecular weight ofbetween about 100,000 to about 350,000. In one embodiment, the foamboards 110 have a molecular weight of between about 120,000 and about150,000 from recycled expanded polystyrene. However, other foams arealso contemplated in other embodiments. It is also contemplated that thefoam boards 110 are sized to between about 600 mm to about 1524 mm widex about 1200 mm to about 2769 mm long. The boards are also contemplatedto be any sheet stock made of any thermoplastic polymer material.

FIG. 2 is a sectional view of the foam board 110. In one exemplaryembodiment, the section lines 2-2 in FIG. 1 are normal to the directionin which the board 110 is extruded. That is, in this exemplaryembodiment, the section 2-2 is across the width of the extruded foamboard. FIG. 2 illustrates that there are typically surface variations200 in the first and second major surfaces 112, 114 across the width ofextruded polystyrene foam boards 110. The surface variations areexaggerated in FIG. 2 to make it clear that surface variations 200 arepresent.

In this application, flatness is the condition of a surface having allelements in one plane. In general, a flatness variation specifies avariation zone defined by two parallel planes within which the surfacelies. In the example illustrated by FIG. 2, the flatness variation F1 isthe distance between two parallel planes 202, 204 that the surface 114lies between. In one exemplary embodiment, the flatness variation of themajor surface 112 and/or the major surface 114 of a piece of a board 110that is 2 feet wide by 2 feet long is greater than 0.020 inches, such asgreater than 0.050 inches, such as between 0.050 and 0.10 inches, suchas between 0.050 inches and 0.08 inches. The original board can be anysize. In one exemplary embodiment, the flatness variation of the majorsurface 112 and/or the major surface 114 of a piece of a two inch thickboard 110 that is 2 feet wide by 2 feet long is greater than 0.020inches, such as greater than 0.050 inches, such as between 0.050 and0.10 inches, such as between 0.050 inches and 0.08 inches. However, theboard may have any width, thickness or length.

In another exemplary embodiment, the flatness variation F1 is estimatedby measuring a thickness variation or range. Referring to FIG. 2A, thethickness range may be determined by measuring the thickness of theboard 110 at various points along the surface of the board, indicated byarrows 250 in FIG. 2. The thickness variation is the difference betweenthe maximum and minimum measured thickness. In one exemplary embodiment,the thickness range of a piece of a board that is 2 feet wide by 2 feetlong is greater than 0.078, such as between 0.078 and 0.15 inches, suchas about 0.125 inches. In one exemplary embodiment, the thickness rangeof a piece of a 2 inch thick board 110 that is 2 feet wide by 2 feetlong is greater than 0.078, such as between 0.078 and 0.15 inches, suchas about 0.125 inches. However, the board may have any width, thicknessor length. In one exemplary embodiment, the initial flatness variationF1 of a board 110, that has not been flattened as will be described inmore detail below, is estimated by dividing the thickness variation bytwo. This is based on the assumption that the flatnesses of the majorsurfaces are initially similar.

FIG. 3 illustrates a first polystyrene board 110 stacked on top of asecond polystyrene board 110. As is illustrated by FIG. 3, the abutmentbetween the major surface 114 of the top board with the major surface112 of the bottom board is not flush due to flatness variations of themajor surfaces. As such, when polystyrene boards 110 having largeflatness variations are heat laminated together using existingtechniques, voids 302 would be expected to form between the two boardsin the bond area 304. The two boards 110 would not be bonded together inthe area of the voids 302. These voids/unbounded areas 302 would makeheat laminated boards made using existing techniques unsuitable for someapplications. For example, smaller foam pieces 2400 (See FIG. 24) usedto make machined foam parts need to be void free, or the machined partwill have unacceptable surface imperfections.

FIGS. 4, 4A, and 4B are taken from U.S. Pat. No. 4,608,103, whichdiscloses an example of an existing technique for heat laminating twofoam boards together. Referring to FIG. 4, the foam board 110 is fedinto the apparatus on a platform defined by a series of rollers 426which support the board 110 in a horizontal plane.

In the prior art FIG. 4 example, the forward end of the bottom or lowerboard is positioned under an elongated flat stainless steel heatingstrip or blade 430 which extends horizontally across the width of thefoam board 110 and has opposite end portions attached to a pair ofhorizontal support plates 432. The plates 432 also support a spreadermember or bar 436 which is spaced with the heating blade 30 above thesupport rollers 426 by a distance slightly greater than the thickness ofthe foam board 110.

In the prior art FIG. 4 example, each of the plates 432 is supported bya pair of machine screws 439 which are threaded into corresponding nutssecured to an angle member 442. Another pair of nuts are threaded ontothe screws 439 for vertical adjustment and support the correspondingplate 432 so that it may move or float vertically by a predetermineddistance according to the position of the nuts below the heads of thescrews 439. The vertical spacing of the blade 430 and the bar 436 abovethe rollers 426 may be adjustably selected according to the thickness ofthe lower foam board 416, by means of the machine screws 439.

In the prior art FIG. 4 example, the spreader bar 436 forms a supportfor the upper foam board when the board is inserted into the apparatusand positioned directly above the lower foam board in verticalalignment. The spreader bar 436 is positioned slightly above the levelof the heating blade 430 so that the forward end of the upper foam boarddoes not contact the heating blade 430 when the foam board is firstpositioned within the apparatus directly above the lower foam board. Apair of vertically spaced pressure members or rolls 450 are positionedabove and below the heating blade 430, and are driven in oppositedirections. The drive system or mechanism for the rolls 450 provides foradjusting the upper rolls 450 in a vertical plane in order to vary thespacing or gap defined between the rolls 450. The speed of the motor 452is selected according to the desired processing rate, and a controller456 is connected by conductors to a temperature sensing element orthermocouple recessed within the leading edge of the heating blade 430.

In operation of the prior art apparatus illustrated by FIG. 4, forheat-fusing or welding the lower side surface of the upper foam board tothe upper side surface of the lower foam board, the rolls 450 areadjusted to define a gap 454 which is slightly less than the combinedthicknesses of the foam boards. The heating blade 430 is energized to apredetermined temperature, for example, 500° F. The foam boards are thenadvanced forwardly until the leading ends of the boards enter the gap454 which causes the opposing side surfaces of the foam boards tocontact the upper and lower sides of the heating blade 430. Thetemperature of the blade 430 is selected to soften the skin or surfaceportions of the foam boards after which the softened surfaces arepressed together by the rolls 450.

As the driven rolls 450 feed the foam boards through the gap 454, theopposing side surfaces of the boards are uniformly heated by the blade430 along the full length of the boards and are then fused together toform the interface or bond area 304. Since the thickness of each foamboard varies somewhat along its length, for example, by plus or minus1/16 inch, the heating element or blade 430 is permitted to shift orfloat vertically as a result of the movement of the support plates 432on the screws 439.

Prior art U.S. Pat. No. 4,608,103 alleges that a uniform pressurecontact is made against the heating blade 430 by each of the foamboards. Prior art U.S. Pat. No. 4,608,103 also alleges that thisprovides for a uniform and dependable weld at the interface 304 byassuring uniform heating and softening of the opposing side surfaces ofthe foam boards. Applicant believe that the arrangement disclosed byprior art U.S. Pat. No. 4,608,103 cannot provide a uniform pressurecontact along the entire width of two foam boards that each havesubstantial flatness variations, since the heating blade 430 can onlyfollow the contour of one of the foam boards, not both. As such, thesingle heating blade 430 arrangement disclosed by Prior art U.S. Pat.No. 4,608,103 cannot provide for a void-free weld between foam boardsthat have substantial flatness variations, such as the boardsillustrated by FIG. 3 and described above.

Applicant has found that in arrangements where foam boards pass againsta stationary heating element (Similar to the heating blade illustratedby FIGS. 4, 4A, and 4B), melted foam material 600 (See FIGS. 4, 4B and6) has a tendency to accumulate on the heating stationary heatingelement. Once an excessive amount of material 600 accumulates on thestationary heating element, the material 600 drips off of the heatingelement and drips onto the lower of the two boards 110 that are beinglaminated together. This hot material 600 melts trenches 602 thatresemble “worm hole” into the foam material of the lower of the twoboards 110. The hot material 600 cools and forms an area 610 of materialthat is much harder and much denser than the other foam material at thesame depth.

In addition to the voids/unbonded areas 302, the trenches 602 and areas610 of harder and denser material make heat laminated boards made usingexisting techniques unsuitable for some applications. For example, aswill be described in more detail below, smaller foam pieces 2400 (SeeFIG. 24) used to make machined foam parts need to be void free or themachined part will have unacceptable surface imperfections. In addition,the location of higher density material of laminated foam pieces must beknown and accounted for, or cutting operations will result inunacceptable surface imperfections. The location and depth of thetrenches 602 and areas 610 of harder/denser material is random andtherefore unpredictable. As such, the areas 610 of harder/densermaterial cannot be accounted for in a cutting operation, When a sawblade or other cutting tool unexpectedly hits one of the areas 610 ofharder/denser material, a surface imperfection occurs and/or the part isotherwise damaged.

FIG. 7 is illustrates an exemplary embodiment of an apparatus 700 forflattening a major surface 112 or 114 of a foam board 110. In theillustrated embodiment, the apparatus 700 flattens only one majorsurface 114 of the foam board 110. In another exemplary embodiment, theapparatus 700 flattens both major surfaces 112, 114 of the foam board110. In the illustrated embodiment, the apparatus 700 applies heat(indicated by arrows 702) and pressure (indicated by arrows 704) to thefoam board 110 to flatten the major surface 114.

The pressure may be applied to the foam board 110 in a wide variety ofdifferent ways. In the example illustrated by FIG. 7, the pressure isapplied to the foam board 110 by a clamping device 710. The illustratedclamping device includes an upper clamp member 712 and a lower clampingmember 714. The upper clamp member 712 applies pressure to the majorsurface 112 and the lower clamp member 714 applies pressure to the majorsurface 114. The upper and lower clamp members can take a wide varietyof different forms. For example, when the board is moved through theapparatus 700 during the flattening, the upper and lower clamp members712, 714 may comprise rollers and/or belts, which may be driven by amotor. If the board is stationary during the flattening operation, theclamp members 712, 714 may comprise plates that are sized to engage theentirety of the major surfaces 112, 114.

The heat may be applied to the major surface 114 in a wide variety ofdifferent ways. The heat may be applied to the major surface 114 beforethe application of pressure, during the application of pressure, and/orafter the application of pressure. In one exemplary embodiment, the heatis applied to the major surface 114 by one or more heating elements thatare contained in the lower clamp member 714. The heating elements cantake a wide variety of different forms. The heating element can utilizeelectricity, a heated fluid, such as oil, water, or other liquids thatare provided to the heating element and/or a fuel to provide the heat tothe major surface 114. If both sides of the board 110 are to beflattened, the same heating type of heating element can be provided onboth sides of the board 110 by the apparatus 700.

FIG. 8 illustrates the foam board 110 shown in FIG. 2 that has beenflattened in accordance with the teachings of the present application toprovide a flattened major surface 814. As can be seen by comparing FIG.8 with FIG. 2, the flattened major surface 814 has a much smallerflatness variation than the unprocessed major surface 114. For example,the major surface 814 may be flatter that the major surface 114 by afactor of two, a factor of 4, a factor of 10, or even more comparativelyflatter than an unprocessed extruded polystyrene board. In one exemplaryembodiment, the flatness variation of the major surface 112 and/or themajor surface 114 of a piece of a board 110 that is 2 feet wide by 2feet long is less than 0.040 inches, such as less than 0.030 inches,such as less than 0.020 inches, such as less than 0.010 inches, such asless than 0.050 inches. In one exemplary embodiment, the flatnessvariation of the major surface 112 and/or the major surface 114 of apiece of a board 110 that was originally 2 inches thick, that is 2 feetwide by 2 feet long is less than 0.040 inches, such as less than 0.030inches, such as less than 0.020 inches, such as less than 0.010 inches,such as less than 0.005 inches. However, the board may have any width,thickness or length.

Referring again to FIGS. 8 and 2, in one exemplary embodiment theflattened board has a much smaller thickness variation than theunprocessed board. The thickness variation in FIG. 8 can be measured inthe same manner as in FIG. 2A. In one exemplary embodiment, thethickness range of a piece of a board (flattened on one side) that is 2feet wide by 2 feet long is less than 0.078, such as less than 0.062inches, such as less than 0.031 inches. In one exemplary embodiment, thethickness range of a piece of a 2 inch thick board that is 2 feet wideby 2 feet long is less than 0.078, such as less than 0.062 inches, suchas less than 0.031 inches. However, the board may have any width,thickness or length.

In one exemplary embodiment, the processed flatness variation F2 of aflattened major surface of a board that has been flattened on one sideis calculated by the following equation:

F2=(T½)−T2 where:

F2 is the processed flatness variation;

T2 is the processed thickness variation; and

T1 is the original thickness variation.

For example, if a board 110 has an initial thickness variation of 0.126inches and a thickness variation of 0.059 after processing as describedwith respect to FIG. 8, the flatness variation F2 is 0.004 inches(0.126/2−0.059). This calculation of the flatness variation assumes thatthe initial surface imperfections are of the same size on the top andbottom major surfaces and therefore contribute equally to the initialthickness variations of the board. That is, the initial flatnessvariation F1 is the same on the top major surface as the bottom majorsurface.

Referring to FIG. 8, the heating and application of pressure produces alayer 800 of molten material (temporarily, until the material cools andsolidifies). This layer 800 of molten material on the flattened majorsurface 814 allows the boards to be heat laminated together withoutusing an external adhesive and such that the adhesion of the boards isuniform across over the entirety of the facing major surfaces. FIG. 9illustrates a first polystyrene board 110 having a flattened majorsurface 814 stacked on top of a second polystyrene board 110 having aflattened major surface 814. As is illustrated by FIG. 9, the abutmentbetween the flattened major surface 814 of the top board with theflattened major surface 814 of the bottom board is substantially flushdue to the abutting major surfaces 814 being substantially flat. Assuch, when polystyrene boards 110 are heat laminated together, the voids302 (See FIG. 3) are eliminated between the two boards in the bond area304 (See FIG. 13). The elimination of the voids/unbounded areas 302makes heat laminated foam boards suitable for some applications, such asfoam pieces 2400 (See FIG. 24) used to make machined foam parts.

FIG. 10 is a flowchart that illustrates an exemplary embodiment of amethod 1000 of making a heat laminated foam board 1300 (See FIG. 13).FIGS. 11, 12 and 18 illustrate examples of apparatus that can be used toperform the method and make a heat laminated foam board 1300. Accordingto the method, first and second boards 110 a, 110 b are positioned(steps 1002, 1004) relative to one another such that the major surfacesurfaces of the boards are substantially aligned. In the examplesillustrated by FIGS. 11 and 18, a first foam board 110 a is positionedabove a second foam board 110 b.

Referring to FIG. 10, a major surface 112 or 114 of each board isindependently flattened 1006. That is, the flattening of the majorsurface 114 of the first board 110 a is separate and independent fromthe flattening of the major surface 112 of the second board 110 b. Inthe example illustrated by FIG. 11, an independent flatteningarrangement 1100 comprises two of the apparatuses 700 illustrated byFIG. 7. An upper flattening apparatus 700 a flattens the bottom majorsurface 114 of the first board 110 a. In the illustrated embodiment, thelower flattening apparatus 700 b is the same as the upper flatteningapparatus 700 b, except it is flipped over (i.e. the heated member 714is on the top and the non-heated member is on the bottom. The lowerflattening apparatus 700 b flattens a major surface 112 or 114 of thesecond board 110 b.

In the example illustrated by FIG. 18, each of the upper and lowerflattening apparatuses 700 a, 700 b, comprise a heated clamping member714, in the form of a roller, and a clamping roller 712 that is notheated. In the exemplary embodiment illustrated by FIG. 18, theapparatus 1100 includes optional downstream heating elements 770. Therollers 714, 712 clamp against the boards 110 a, 110 b to flatten themajor surface 114 of the board 110 a and the major surface 114 of theboard 110 b. In the illustrated exemplary embodiments, the flattening ofeach of the two board is achieved using heat and pressure. The optionaldownstream heating elements 770 are positioned between the flattenedsurfaces 814. The heating elements 770 apply heat to control thetemperature of the layer 800 of molten material. The heating elements770 can take a wide variety of different faints. The optional heatingelements 770 can take any form that allows the temperature of the layer800 of molten material to be controlled and kept in a melted state untilthe boards 110 a, 110 b reach the pressing apparatus 1210. In theillustrated embodiment, the heating elements 770 are elongated rods thatare spaced apart from the flattened surfaces 814, downstream from therollers 714. However, the heating elements can have other shapes, suchas plates. In one exemplary embodiment, the heating elements 770 spanthe width of the boards 110, 110 b. In one exemplary embodiment, theheating elements 770 are individually controllable.

In one exemplary embodiment, the flattened surfaces 814 of the boardsproduced according to the method 1000 are flattened by a factor of two,a factor of four, a factor of 10, or even more comparatively flatterthan an unprocessed extruded polystyrene board. In one exemplaryembodiment, the flatness variation of the major surface 814 of a pieceof a board 110 that is 2 feet wide by 2 feet long is less than 0.040inches, such as less than 0.030 inches, such as less than 0.020 inches,such as less than 0.010 inches, such as less than 0.050 inches. In oneexemplary embodiment, the thickness variation range of a piece of aboard (flattened on one side) that is 2 feet wide by 2 feet long is lessthan 0.078, such as less than 0.062 inches, such as less than 0.031inches.

In an exemplary embodiment, the outer skin 124 is not removed during theindependent flattening step 1006. In an exemplary embodiment, a layer ofmolten material 800 is formed on the flattened surfaces 814. In theexample illustrated by FIG. 18, the heated rollers 714 becomes coatedwith the molten board material 800. After an initial, start-up orpriming of the heated roller 714, the heated roller 714 attains a steadystate. That is, the rate at which molten board material 800 is depositedon the roller 714 equals the amount of molten material that leaves theheated roller 1114 and is deposited on the flattened surface 814. Assuch, the trenches 602 and areas 610 shown in FIGS. 5 and 6 do not form.

Referring to FIGS. 10, 12, and 18, the boards 110 a, 110 b are pressedtogether 1010 to form the thicker laminated board 1300. In the examplesillustrated by FIGS. 12 and 18, the flattened surfaces 814 are pressedtogether. The molten material 800 fills any remaining flatnessvariations in the board surfaces 812. When the molten material 800cools, the material solidifies to uniformly bond the two boards 110 a,110 b together across the flattened surfaces 814. FIG. 13 illustratesthe formed laminated board 1300.

The boards 110 a, 110 b may be pressed together in a wide variety ofdifferent ways. In the example illustrated by FIG. 12, the pressure isapplied to the boards 110 a, 110 b by a clamping device 1210. Theillustrated clamping device includes an upper clamp member 1212 and alower clamping member 1214. The upper clamp member 1212 applies pressureto the board 110 a and the lower clamp member 1214 applies pressure tothe board 110 b. The upper and lower clamp members can take a widevariety of different forms. For example, when the board is moved throughthe clamping device 1210, the upper and lower clamp members 1212, 1214may comprise rollers, flat plates, belts or a combination thereof. Ifthe board is stationary during pressing operation, the clamp members1212, 1214 may comprise plates that are sized to press the entirety ofthe boards 110 a, 110 b together. In the example illustrated by FIG. 18,the clamping device 1210 comprises rollers. The clamp members 1212, 1214clamp against the boards 110 a, 110 b together to form the thickerlaminated foam board 1300.

FIG. 13 illustrates the formed laminated board 1300 and FIG. 14illustrates and enlarged portion of FIG. 13 that illustrates a bond area304 between the polystyrene boards. In FIG. 14, the variations inthickness of the bond area are highly exaggerated to illustrate thevariation. In an exemplary embodiment, the combination of theindependent flattening of the surfaces 814 and the uniform distributionof the molten material 800 by the rollers 714 across the surfaces 814results in a very small bond thickness variation. That is, the thicknessof the denser material 1302 that forms the bond between the two boardsvaries by only a small amount. The bond thickness variation is shown inFIG. 14 as the difference between the minimum thickness T_(MIN) and themaximum thickness T_(MAX) of the bond material. In one exemplaryembodiment, the bond area between each of the polystyrene boards issubstantially planar and the bond thickness variation is less than 0.020inches, or less than 0.015 inches. In one exemplary embodiment, theaverage bond thickness is between 0.015 and 0.045 inches, such asbetween 0.020 and 0.040 inches, such as between 0.025 and 0.035, such asabout 0.030 inches, with a corresponding bond thickness variation ofless than 0.020 inches, or less than 0.015 inches.

FIG. 14A illustrates another method for measuring variations in the bondarea. In the example illustrated by FIG. 14A, the laminated board 1300is cut to expose the plane illustrated by FIG. 14A. Points 1410 and 1412on the bottom of the bond area 304 at the edges 122, 120 of the boardare identified. Points 1420 and 1422 are marked a fixed distance belowthe points 1410 and 1412. A reference line 1424 is drawn between thepoints 1420 and 1422. The sample may be cut along the line 1422.Distances indicated by pairs of arrows 1430 are measured. In oneexemplary embodiment, the variation (i.e. the difference between themaximum distance and the minimum distance) between the distances 1430 isless than 0.100 inches, less than 0.075 inches, less than 0.050 inches,or less than 0.020 inches.

FIGS. 15-17 illustrate that a multi-layer the laminated board 1700 (SeeFIG. 17) may be formed from three or more boards 110. In one exemplaryembodiment, the flattening arrangement 1100 and the clamping device 1210may be adjustable to accommodate laminating of multiple boards togetherand to accommodate laminating of boards having different thicknesses.FIGS. 15 and 16 illustrate that use of the flattening arrangement 1100and the clamping device 1210 to add boards 110 to add layers and form amultiple layer heat laminated foam board 1700. In the exampleillustrated by FIG. 15, a single board 110 is added. However, in otherembodiments, laminated boards 1300 and/or 1700 can be laminated togetherto add more than one layer at a time.

FIG. 15 illustrates that a foam board 110 is positioned relative to alaminated foam board 1300 such that the major surface surfaces of theboards are substantially aligned. In the example illustrated by FIG. 15a foam board 110 is positioned below a laminated foam board 1300.However, in other embodiments, the laminated board 1300 can bepositioned on the bottom. In the example illustrated by FIG. 15, theupper flattening apparatus 700 a is adjustable to accept the laminatedfoam board 1300. In another embodiment, the lower flattening apparatus700 b is adjustable to accept a laminated foam board or different sizedboards. In one exemplary embodiment, the upper flattening apparatus 700a is adjusted by vertically adjusting the position of the upper clampmember 712, while the lower clamp member 714 remains in a fixedposition. As such, the vertical position of the surface 1314 beinglaminated is not changed by the adjustment. In one exemplary embodiment,if the lower flattening apparatus 700 b is adjustable, it is adjusted byvertically adjusting the position of the lower clamp member 714, whilethe upper clamp member 714 remains in a fixed position. As such, thevertical position of the surface 1314 being laminated is not changed bythe adjustment.

Referring to FIG. 15, a major surface 1314 of the laminated board 1300and a major surface 112 or 114 of the board 110 is independentlyflattened. That is, the flattening of the major surface 1314 is separateand independent from the flattening of the major surface 112 of theboard 110 being added. In the illustrated exemplary embodiments, theflattening of each of the two board is achieved using heat and pressure.In one exemplary embodiment, the flattened surfaces 814, 1314 of theboard 110 and the laminated board 1300 are flattened by a factor atleast two, a factor of four, a factor of 10, or even more comparativelyflatter than an unprocessed extruded polystyrene board or theunprocessed outer surfaces of the laminated board 1300. In one exemplaryembodiment, the flatness variation of the major surface 814 and themajor surface 1314 a piece of a board that is 2 feet wide by 2 feet longis less than 0.040 inches, such as less than 0.030 inches, such as lessthan 0.020 inches, such as less than 0.010 inches, such as less than0.050 inches. In one exemplary embodiment, the thickness variation rangeof a piece of aboard 110 and 1300 (each flattened on one side) that is 2feet wide by 2 feet long is less than 0.078, such as less than 0.062inches, such as less than 0.031 inches.

In an exemplary embodiment, outer skins 124 (See FIGS. 1 and 2) of theboard 110 and the boards of the laminated board 1300 are not removedduring the independent flattening. In an exemplary embodiment, a layerof molten material 800 is formed on the flattened surfaces 812, 1314.Referring to FIG. 18, in an exemplary embodiment the heated rollers 714becomes coated with the molten board material 800. After an initial,start-up or priming of the heated roller 714, the heated roller 714attains a steady state. That is, the rate at which molten board material800 is deposited on the roller 714 equals the amount of molten materialthat leaves the heated roller 714 and is deposited on the flattenedsurface 814, 1314. As such, the trenches 602 and areas 610 shown inFIGS. 5 and 6 do not form between any of the layers of the multiplelayer laminated board 1700.

Referring to FIG. 16, the laminated board 1300 and the board 110 arepressed together 1010 to form the thicker, multi-layer, laminated board.In the example illustrated by FIGS. 16, the flattened surfaces 814, 1314are pressed together. The molten material 800 fills any remainingflatness variations in the board surfaces 814, 1314. When the moltenmaterial 880 cools, the material solidifies to uniformly bond thelaminated board 1300 to the board 110 together across the flattenedsurfaces 814, 1314. FIG. 17 illustrates the formed multi-layer laminatedboard 1700.

The laminated board 1300 may be pressed together with the board 110 in awide variety of different ways. The clamping device 1210 illustrated byFIG. 12 may be adjusted to accept the increased thickness of thelaminated board. In one exemplary embodiment, the upper clamping member1212 is vertically adjusted to accept the laminated board 1300 and thelower clamping member 1214 is not adjusted. This configurationcorresponds to the embodiment where the upper flattening apparatus 700 ais adjusted to accommodate the thicker laminated board 1300 and thelower flattening apparatus is not adjusted and flattens single thicknessboards. In another embodiment the lower clamping member 1214 isvertically adjusted and the upper clamping member is fixed. Thisembodiment corresponds to the laminated board being flattened with thelower flattening apparatus. In another embodiment, the position of boththe upper clamping member 1214 and the lower clamping member 1214 areadjustable. This embodiment corresponds to an embodiment where both theupper and lower flattening apparatuses 700 a, 700 b are verticallyadjustable to accommodate different thickness boards and/or laminatedboards.

Referring to FIG. 16, pressure is applied to the laminated board 1300and the board 110 by the clamping device 1210. In the illustratedembodiment, the upper clamp member 1212 applies pressure to thelaminated board 300 and the lower clamp member 1214 applies pressure tothe board 110.

FIG. 17 illustrates the formed multi-layer laminated board 1700. In anexemplary embodiment, the combination of the independent flattening ofthe surfaces 1314, 814 and the uniform distribution of the moltenmaterial 800 by the rollers 714 across the surfaces 1314, 814 results ina very small bond thickness variation. That is, the thickness of thedenser material 1314 that forms the bond between the two boards variesby only a small amount. In an exemplary embodiment, in addition to thebond thickness variation of a single board being very small, the bondthickness variation between all of the bonds of a multi-layer laminatedboard is also very small. That is each of the bonds may be substantiallythe same thickness and the bond thickness varies only a small amount. Inone exemplary embodiment, the bond areas 304 between each of thepolystyrene boards is substantially planar and a bond thicknessvariation between two bonds that laminate three boards together is lessthan 0.020 inches, or less than 0.015 inches. In one exemplaryembodiment, the average bond thickness is between 0.015 and 0.045inches, such as between 0.020 and 0.040 inches, such as between 0.025and 0.035, such as about 0.030 inches, with a corresponding bondthickness variation of less than 0.020 inches, or less than 0.015inches.

In one exemplary embodiment, the bond areas 304 between each of thepolystyrene boards have variations as measured in the manner describedwith respect to FIG. 14A are each less than 0.100 inches, less than0.075 inches, less than 0.050 inches, or less than 0.020 inches.

FIGS. 19, 20 and 23 illustrate simplified component diagrams ofexemplary systems 1910, 2010, and 23, respectively, for laminating aplurality of foam boards is illustrated in accordance with the methoddescribed above. With reference to FIG. 19, for purposes ofillustration, the system 1910 is described with reference to laminatingtwo (2) boards 110 a, 110 b (e.g., foam boards) together to form alaminated foam board 1300 or 1700. In addition, it is contemplated thateach of the two foam boards 110 a, 110 b is between about ½″ to about 8″thick so that the laminated foam board 1300 is between about ⅞″ to about16″ thick. It is also contemplated, as discussed in more detail below,that each of the two (2) foam boards 110 a, 110 b may be comprised ofmultiple layers of foam that have been thermally laminated together, sothat the laminated foam board 1300 is between about 1¾″ and 32″ thick.In one embodiment, each of the two foam boards 110 a, 110 b is betweenabout 1 15/16″ and about 1 31/32″ thick and the resulting laminated foamboard is between about 3¾″ and about 3 15/16″ thick. The thickness ofthe laminated board 1300 is less than the total thickness of theoriginal foam boards 110 a, 110 b due to a bond area or thermo weldportion 304 created at the interface between faces of the original foamboards 110 a, 110 b. As discussed in more detail below, the bond area orthermal weld portion 304 is relatively denser foam, which is illustratedas a relatively heavier line as opposed to cells in the remainder of thelaminated board 1300 or 1700 and the original foam boards 110 a, 110 b.The relatively denser foam results in a reduced thickness of thelaminated foam board 1300 or 1700. In the illustrated embodiment, thebond area or thermal weld portion 304 is contemplated to be betweenabout 1/64″ and about ⅛″ thick.

The system 1910 illustrated by FIG. 1910 includes a waiting frame 1924(e.g., a waiting station), a heating and flattening station 1926, apressing station 1930, and a receiving station 1932. The heating frameand flattening station 1926 and the pressing station 1930 are referredto as a foam board laminator. Each of the waiting frame 1924, theheating and flattening station 1926, the pressing station 1930, and thereceiving frame 1932 includes a respective transport system for movingthe foam boards 110 a, 110 b through the frame. As illustrated, thewaiting frame 1924, the heating and flattening station 1926, thepressing station 1930, and the receiving frame 1932 are positionedsequentially so that the foam boards 110 a, 110 a are passed from thewaiting frame 1924 to the heating and flattening frame 1926, passed fromthe heating and flattening frame 1926 to the pressing frame 1930, andthen passed from the pressing frame 1930 to the receiving frame 1932.

The waiting frame 1924 is used for preparing and aligning the foamboards 110 a, 110 b to be laminated together. In an exemplary methodillustrated by FIG. 21, in a step 2100, the first foam board 110 a ispositioned on the waiting frame 1924. In a step 2120, the second foamboard 110 b is positioned above, and spaced from, the first foam board110 a so that a face 114 of the first foam board 110 a is adjacent andopposes (e.g., faces) a face 114 of the second foam board 110 b.

Respective leading edges 116 of the first and second foam boards 110 a,110 b are aligned, in a step 2140, in the waiting frame 1924. Aligningthe leading edges 116 helps ensure an even and smooth leading edge 1950(See FIG. 18) of the laminated foam board 1300 or 1700.

Referring to FIG. 19, in one embodiment the first foam board 110 a isset on an upper rail 1952 of the waiting frame 1924. The upper rail 1952is movable between a closed position and an open position. The upperrail 1952 is in the closed position when the first foam board 110 a isset on the upper rail 1952. An optional sensor (e.g., a photoelectriccell sensor) senses the presence of the first foam board 110 a on theupper rail 1952 and transmits a signal to a control circuit (not shown)to switch the upper rail 1952 to the open position. When the upper rail1952 moves to the open position, the first foam board 110 a drops onto alower rail 1956. After the first foam board 110 a is on the lower rail1956, the sensor senses the absence of the first foam board 110 a on theupper rail 1952, and transmits a signal to the control circuit (notshown) to switch the upper rail 1952 back to the closed position. Oncethe upper rail 1952 is again in the closed position, the second foamboard 110 b is set on the upper rail 1952. The upper and lower rails1952, 1956, respectively, act as a spacer to create and maintain aninitial space between the faces 114 of the first and second foam boards110 a, 110 b (See FIG. 23). In one embodiment, it is contemplated thatthe initial space between the first faces 114 of the first and secondfoam boards 110 a, 110 is determined by a height setting of the lowerrail 1956, which is adjustable to suit various board thicknesses. Forexample, the lower rail 1956 may be lowered to accommodate thickerboards and raised to accommodate thinner boards.

Once the first foam board 110 a is positioned on the lower rail 1956 andthe second foam board 110 b is positioned on the upper rail 1952, apusher plate 1960 (e.g., a pusher) is activated. Referring to FIG. 23,the pusher plate 1960 aligns the foam boards 110 a, 110 b by pushingtrailing edges 118 of the foam boards 110 a, 110 b so that the leadingedges 116 of the foam boards 110 a, 110 b contact an optional stop. Thepusher plate 1960 pushes the foam boards 110 a, 110 b toward an entrance1970 of the heating and flattening frame 1926.

Referring to FIG. 19, an exemplary space of 250 mm is between thewaiting frame 1924 and the heating frame 1926. An exemplary space of 150mm is between the heating and flattening frame 1926 and the receivingframe 1932. Although specific spaces of 250 mm and 150 mm areillustrated between the waiting frame 1924 and the heating frame 1926and between the heating frame 1926 and the receiving frame 1932,respectively, it is to be understood that the spaces between the waitingframe 1924 and the heating frame 1926 and between the heating frame 1926and the receiving frame 1932 are adjustable. For example, the spacebetween the heating frame 1926 and the receiving frame 1932 may beincreased for thicker foam boards.

In a step 2160, the foam boards 110 a, 110 b are received at theentrance 1970 of the heating and flattening frame 1926. As the foamboards 110 a, 110 b are pushed into the heating frame 1926 by the pusherplate 1960, the foam boards 110 a, 110 b engage a means for passing 1972the foam boards 110 a, 110 b from the entrance 1970 of the heating andflattening frame 1926 to an exit 1974 of the heating and flatteningframe 1926.

In the exemplary embodiment Illustrated by FIG. 19, the means forpassing 1972 comprises the rollers of the flattening apparatuses 700 a,700 b illustrated by FIG. 18.

In the example illustrated by FIG. 19, each of the upper and lowerflattening apparatuses 700 a, 700 b, comprise a heated roller 714 and aroller 712 that is not heated. In addition to the rollers 714, 712, themeans for passing 1972 may includes additional drive rollers 1992. Allof the rollers 714, 712, 1992 may be driven by horizontal shafts. Therollers 714, 712 clamp against the boards 110 a, 110 b to flatten thebottom major surface 112 or 114 of the board 110 a and the top majorsurface 112 or 114 of the board 110 b. In the illustrated exemplaryembodiments, the flattening of each of the two boards is achieved usingheat and pressure applied by the rollers 714, 712. In the exemplaryembodiment illustrated by FIG. 19, the heating and flattening frame 1926also includes the optional downstream heating elements 770.

In an exemplary embodiment, a layer of molten material 800 is formed onthe flattened surfaces 812, 814. Referring to FIG. 19, in an exemplaryembodiment the heated roller 814 becomes coated with the molten boardmaterial 800. After an initial, start-up or priming of the heated roller814, the heated roller 814 attains a steady state. That is, the rate atwhich molten board material 800 is deposited on the roller 714 equalsthe amount of molten material that leaves the heated roller 714 and isdeposited on the flattened surface 812, 814. As such, the trenches 602and areas 610 shown in FIGS. 5 and 6 do not form. In an exemplaryembodiment, the optional downstream heating elements 770 keep the layerof molten board material in a melted state as the boards are fed intothe pressing frame 1930.

FIG. 20 illustrates another exemplary embodiment of a system 2010 forlaminating a plurality of foam boards. The system 2010 illustrated byFIG. 20 is substantially similar to the system 1910 illustrated by FIG.19, except the heating and flattening frame 1926 is replaced withanother embodiment of a heating frame 2026. In the example illustratedby FIG. 20, a means for passing 2072 the foam boards 110 a. 110 bthrough the heating frame 2026 includes at least one pair of chains2076, 2080 driven by respective vertical shafts 2082, which in turn aredriven by a motor (not shown) turning respective sprockets on thevertical shafts 2082. In the illustrated embodiment, the at least onechain 2076, 2080 is driven by the sprockets on rollers mounted on thevertical shafts 2082. However, other methods for driving the at leastone chain 2076, 2080 are also contemplated.

With reference to FIG. 22, a top view of the pair of the chains 2080illustrates that the chains 2080 include spikes 2090 that engage (e.g.,impale) the foam board 110 b as the foam board 110 b passes through theheating frame 1926 (see FIG. 20). The engagement of the spikes 2090 withthe foam board 110 b moves the foam board 110 b through the heatingframe 2026 (see FIG. 20) as the pair of chains 2080 is driven by thevertical shafts 2082. The engagement of the spikes 2090 with the foamboard 110 b also facilitates keeping the foam board 110 b positionedrelatively flat, level, and relatively parallel with respect to theother foam board 110 a (see FIG. 20). The engagement of the spikes 1990with the foam board 110 b facilitates keeping the foam board 110 bsuspended above the heating element 2106 so the foam board 110 b doesnot touch the heating element 2106. Spikes (not shown) on the chains2076 act to engage (e.g., impale) the foam board 110 a, in a mannersimilar to the way the spikes 2090 engage the foam board 110 b, to movethe foam board 110 a through the heating frame 1926 (see FIG. 20) as thepair of chains 2076 is driven by the vertical shafts 2082. Theengagement of the spikes (not shown) with the foam board 110 a alsofacilitates keeping the foam board 110 a positioned relatively flat,level, and relatively parallel with respect to the other foam board 110b (see FIG. 20) and suspended below the heating element 2106 so the foamboard 110 a does not touch the heating element 2106.

FIG. 23 illustrates another exemplary embodiment of a system 2310 forlaminating a plurality of foam boards. The system 2310 illustrated byFIG. 23 is substantially similar to the system 2010 illustrated by FIG.20, except the heating frame 2026 is replaced with another embodiment ofa heating frame 2326. With reference to FIG. 23, in this embodiment ameans for passing 2372 the foam boards 110 a, 110 b through the heatingframe 2326 includes a mechanism having rollers 2392 driven by respectivevertical shafts 2394, which in turn are driven by a motor (not shown)turning respective sprockets on the vertical shafts 2394. The rollers2392 frictionally engage the foam boards 110 a, 110 b. First and secondroller conveyors 2300, 2302 facilitate maintaining the first and secondfoam boards 110 a, 110 b respectively, positioned relatively flat,level, and relatively parallel with respect to each other. Angle gearboxes 2304 permit angular adjustment of the first roller conveyor 2300to ensure the first roller conveyor 2300 is substantially parallel tothe first foam board 110 a. Angle gear boxes, although not illustrated,are also contemplated for similarly permitting angular adjustment of thesecond roller conveyor 2302 to ensure the second roller conveyor 2302 issubstantially parallel to the second foam board 110 b. Otherembodiments, in which the mechanism is a tapered plate or a Tefloncoated conveyor belt system are also contemplated.

In the exemplary embodiment illustrated by FIG. 19, the first and secondfoam boards are heated and flattened as described with respect to FIGS.7, 11, and 18 above. In the exemplary embodiments illustrated by FIGS.20 and 23, the first and second foam boards 110 a, 110 b are positionedso that the face 114 of the first board 110 a and the face 114 of thesecond board 110 b pass by a heating element 2106 (e.g., a heatingplate) as the first and second foam boards 110 a, 110 b pass through theheating frame 2026 or 2326. It is contemplated that the heating element2106 is about the same width as the first and second foam boards 110 a,110 b. In addition, it is contemplated that the heating element 2106 isbetween about 5 mm and about 50 mm thick and, in one embodiment, isbetween about 20 mm and about 30 mm thick. With reference to the waitingframe 1924, it is contemplated that the initial space between the firstfaces 114 of the first foam board 110 a (while on the lower rail 1956)and second foam board 110 b (while on the upper rail 1952) is greaterthan the thickness of the heating element 2106 (See FIG. 23).

The heating element 2106 (or the heated rollers 714 in the FIG. 19embodiment) is heated to a predetermined temperature (e.g., a softeningpoint of the polymer foam). In one embodiment, the predeterminedtemperature is about 240° F., but may be adjusted based on boardproperties, the distance(s) between the heating element 2106 and thefaces 114 of the first and second boards 110 a, 110 b, the speed atwhich the first and second boards 110 a, 110 b pass by the heatingelement 2106, etc. In step 2200 of the method illustrated by FIG. 21,the faces 114 of the first and second boards 110 a, 110 b are heated.More specifically, the faces 114 of the first and second boards 110 a,110 b are simultaneously passed by the heating element 2106 (or againstthe heated rollers 714 in the FIG. 19 embodiment). For example, the face114 of the first board 110 a passes by a first face 2110 (e.g., bottomface) of the heating element 2106 and the face 114 of the second board110 b passes by the a second face 2112 of the heating element 2106. Itis contemplated that the predetermined temperature of the heatingelement 2106, the distances between the heating element 2106 and thefaces 114 of the first and second boards 110 a, 110 b and the length oftime the faces 114 of the first and second boards 110 a, 110 b areexposed to the heat of the heating element 2106 are set to appropriatelyheat the first and second boards 110 a, 110 b for lamination to eachother. It is understood that the length of time the faces 114 of thefirst and second boards 110 a, 110 b are exposed to the heat of theheating element 2106 (or the heated rollers 714 in the FIG. 19embodiment) is determined by the speed at which the means for passing1972 the foam boards 110 a, 110 b through the heating frame 1926travels.

As discussed above, the initial space between the first and second foamboards 110 a, 110 b is determined by a height setting of the lower rail1956, which is adjustable to suit various board thicknesses. Forexample, the lower rail 1956 may be lowered to accommodate thickerboards and raised to accommodate thinner boards. It is contemplated thatthe heating element 2106 and the upper rail 1952 are also adjustable todifferent positions (elevations). Therefore, during operation, anoperator may adjust the position(s) of the lower rail 2156 and/or theheating element 2106 to accommodate the board thickness whilemaintaining a gap between the heating element 2106 and the first face2136 of the first board 110 a. The operator may also adjust theposition(s) of the upper rail 1952 and/or the heating element 2106 toaccommodate the board thickness while maintaining a gap between theheating element 2106 and the face 114 of the second board 110 b (e.g.,an initial gap of between about ⅓2″ and 2″). In one embodiment the gapbetween the heating element 2106 and the face 114 of the first board 110a is adjusted to be about the same size as a gap between the heatingelement 2106 and the face 114 of the second board 110 b (e.g., aninitial gap of between about 1/32″ and 2″). However, other embodiments,in which the gap between the heating element 2106 and the face 114 ofthe first board 110 a is adjusted to be a different size gap thanbetween the heating element 2106 and the face 114 of the second board110 b, are also contemplated. It is also contemplated that not all ofthe upper rail 1952, the lower rail 1956, and the heating element 2106are adjustable to different positions For example, if only the lowerrail 2156 is adjustable, the gap between the heating element 2106 andthe face 114 of the second board 110 b is not adjustable by moving theupper rail 1952 and/or the heating element 2106 and, instead, is set bythe thickness of the second board 110 b.

In each of the embodiments illustrated by FIGS. 19, 20, and 23, the foamboards 110 a, 110 b exit the heating frame 1926, 2026, or 2326 and arereceived at an entrance 2114 of the pressing frame 1930 (See step 2220of the method illustrated by FIG. 21). Rollers 1212, 1214 in thepressing frame 1930 frictionally engage and move the first and secondfoam boards 110 a, 110 b from the entrance 2114 of the pressing frame1930, through the pressing frame 1930, and to an exit 2121 of thepressing frame 1930. In one embodiment, it is contemplated that a heightof the pressing frame entrance 2114 is greater than a height of thepressing frame exit 2121. Therefore, the opening of the pressing frame1930, which is defined by the rollers 1212, 1214, tapers from thepressing frame entrance 2114 to the pressing frame exit 2120. Forexample, in one embodiment, the height of the pressing frame entrance2114 is about 6″, and the height of the pressing frame exit 2121 isabout 4″. As the foam boards 110 a, 110 b pass through the pressingframe 1926 toward the exit 2121, the rollers apply pressure to the faces114 of the first and second foam boards 110 a, 110 b (See step 2240 ofthe method illustrated by FIG. 21). Since the opening of the pressingframe 1930 tapers down to the relatively smaller height of the exit2121, the rollers 1212, 1214 apply progressively higher pressure to thefirst and second foam boards 110 a, 110 b as the foam boards 110 a, 110b move toward the exit 2121. Therefore, the faces 114 are pushed intocontact. Since the faces 114 of the first and second foam boards 110 a,110 b are still warm and include the melted material 800, the faces 114meld together. In other words, the faces 114 form a densified melt andare welded together to form the bond area or thermal weld 304.Therefore, the first and second foam boards 110 a, 110 b are laminatedtogether to form the laminated board 1300 or 1700. The heights of theadhering frame entrance 2114 and the adhering frame exit 2120 may beadjustable.

FIG. 23A illustrates a variation of the heating frames illustrated byFIGS. 20 and 23. In the example illustrated by FIG. 23A, after the firstand second foam boards 110 a, 110 b pass over the heating element 2106,the face 114 of the first board 110 a and the face 114 of the secondboard 110 b pass over a first heated rod 2301 which extends the width ofthe foam boards 110 a, 110 b. The position of the last roll in thesecond roller conveyor 2302 forces the face 114 of the first board 110 ato come in contact with the first heated rod 2301. The position of thelast roll in the first roller conveyor 2300 forces the face 114 of thesecond board 110 b to also come in contact with the heated rod 2301. Thetemperature of the heated rod 2301 combined with the line speed induceadditional molten polystyrene to form on the faces 114 of the foamboards 110 a, 110 b. As the first and second foam boards 110 a, 110 bcontinue to move, they then pass over a second heating rod 2302 which inone embodiment is of a smaller diameter than the first heating rod 2301.The relatively smaller diameter of the second heating rod 2302 comparedwith the first heating rod 2301 allows the foam boards 110 a, 110 b tobend adequately to enter the pressing frame 1930. The temperature of thesecond heating rod 2302 along with the line speed induces the moltenpolystyrene on the face 114 of the first board 110 a and the face 114 ofthe second board 110 b to remain molten in preparation for bonding inthe pressing frame 1930.

FIG. 23B illustrates a variation of the heating and flattening framesillustrated by FIGS. 19, 20, and 23. In the example illustrated by FIG.23B, two pairs of heating and compressing rollers 712, 714 are included.The heating and compressing rollers 712, 714 may be as described withrespect to FIG. 18. The first and second heated rollers or rods 714 aresubstantially the same diameter, but are offset in the horizontal andvertical planes. Both of the heating rods 714 are free to rotate or aredriven to rotate while melting the foam surface. This provides amechanism to prevent the build up of too much molten polystyrene on therods 714 and prevents the molten polystyrene from dripping off the rodsand forming the trenches or “worm holes” described above. The rotatingheating rods 714 apply a uniform coating of molten polystyrene acrossthe entire foam surface.

Although the embodiments discussed above contemplate both the heatingelement 2106 and the first and second heated rods 714, other embodimentsincluding only the heated rods 714 (either of different or substantiallythe same diameters, as discussed in the above embodiments) or only theheating element 2106 are also contemplated.

In another embodiment, it is contemplated that the height of theadhering frame entrance 2114 is the same as the height of the adheringframe exit 2120, and the rollers 1212, 1214 are substantially at thesame distance from each other (e.g., parallel). In this embodiment, therollers 1212, 1214 apply pressure and compress the foam boards 110 a,110 b together (as discussed above) as the foam boards 110 a, 110 b passthrough the pressing frame 1926. The heights of the adhering frameentrance 2114 and the adhering frame exit 2120 may be adjustable.

Whether the rollers 1212, 1214 in the adhering frame 1930 are set up ina tapered or parallel arrangement may be determined as a function of thethickness of the foam boards 110 a, 110 b and a thickness of the heater2106.

Referring to FIGS. 19, 20, and 23, the laminated board 1300 or 1700 ispassed from the exit 2120 of the adhering frame 1930 to the receivingframe 1932. Since being aligned at the waiting frame 1924, the leadingedges 116 of the foam boards 110 a, 110 b remain aligned after the foamboards 110 a, 110 b are laminated into the laminated board 1300 or 1700.

A number of extruded polystyrene foam boards were made on anexperimental basis to illustrate the thermo-lamination effectiveness ofthe embodiments of the present invention. Four of the samples were setforth for the laminating bond strength by tensile strength testaccording to ASTM D1623 as follows:

Sample Adhesive Tensile Strength ID Kpa (psi) Failure Location 1 425(61.52) Sample/test plate weld 2 527 (76.62) Sample/test plate weld 3506 (73.32) Sample/test plate weld 4 402 (58.36) Sample/test plate weldAverage 465 (67.5)  SD 60.8 (8.9)  

Both polystyrene foam boards to be laminated were in the thicknessaround 35 MM (1.4″) each with a density around 27.8 Kg/m³ (1.73 pcf),and tensile strength around 448 Kpa (65 psi).

The laminating bond strength, which is evaluated by tensile strengthtests demonstrate that the adhesive strength between the laminatinglayer at least as strong as the original foam strength.

In one embodiment, it is contemplated that the speeds at which the foamboards 110 a, 110 b move through the waiting frame 1924, the heating andflattening frame 1926, and the adhering frame 1930 are consistent. Forexample, the foam boards 110 a, 110 b move through the heating andflattening frame 1926 at a first speed and move through the adheringframe 1930 at a second speed. In one embodiment, the first speed isabout the same as (e.g., consistent with) the second speed.

Although each of the foam boards 110 a, 110 b discussed above has beendescribed as respective single boards between about ½″ to about 8″thick, it is to be understood that one or both of the foam boards isalso contemplated to be previously laminated. If both of the foam boardswere previously laminated one time, the thickness of the respectivepreviously laminated foam boards may be between about ⅞″ to about 16″thick. The resulting laminated board will then be between about 1⅝″ toabout 32″ thick. Therefore, it is to be understood that the systems1910, 2010, 2310 and methodology for laminating foam boards describedabove may be used repeatedly for previously laminated foam boards, withthe resulting laminated boards becoming thicker and thicker with eachpass through the system 1910, 2010, 2310.

Although the systems 1910, 2010, 2310 have been described with referenceto laminating two (2) foam boards 110 a, 110 b together, it is to beunderstood that simple modifications to the systems 1910, 2010, 2310,such as the adjustability described with reference to FIGS. 15, 16, and18, would accommodate laminating any number of foam boards together. Forexample, additional heating elements would be incorporated into theheating and flattening frame 1926 so additional foam boards may besimultaneously laminated. In addition, it is contemplated that thesystems 1910, 2010, 2310 may accommodate different thicknesses for therespective boards and that the systems 1910, 2010, 2310 may be designedto accommodate foam boards of various densities and thicknesses.

The foam boards may include different surface preparations. In oneembodiment, at least one of the foam boards includes a relatively smoothsurface, which is derived from a process of manufacturing the foamboard. In another embodiment, at least one of the foam boards includes aplanned surface, which is created using an auxiliary cutting processduring which the entire surface of the foam board is machined flat. Inthat embodiment, the faces 114 of the first and second foam boards 110a, 110 b are planed, which exposes cells in the foam board. The planingtechnique makes a much flatter surface facilitating a more uniformsurface adhesion, which is useful in the embodiments disclosed by FIGS.20 and 23. It is also possible to that both of the faces of the foamboards are planned. Foam boards having both faces planned arecontemplated for embodiments including three (3) or more foam boardsadhered together to form a relatively thicker final foam board.

It is contemplated that the systems 1910, 2010, 2310 described above maybe used either off-line, which is a manual operation, or on-line, whichis a more automated process. For example, off-line operation involves anoperator manually placing the first and second foam boards 110 a, 110 bon the waiting frame 1924, as discussed above (from, for example, atransporting facility). On-line operation involves, for example, amachine cutting a continuous strip of foam sheet into the desiredlengths to form the foam boards, which are then deposited on the waitingframe 1924, as discussed above (from, for example, an extruding line).

When the boards are laminated using any of the thermo-processes and/orapparatuses described above, no additional chemicals (e.g., glue) arerequired for the lamination. Without any additional chemicals such asglue, the boards thermo-laminated by the process described above may bemore easily recycled. More specifically, recycled boards from theprocess described above would not include any contaminants (e.g., glue)and, therefore, result in a “cleaner” recycled product. In addition,boards laminated using additional chemicals (e.g., glue) are moredifficult to cut using a hot wire, since a hot wire does not meltthrough hardened glue as easily as the foam boards. Consequently, foamboards laminated using chemicals such as glue may need to be cut using acutter such as a router.

FIG. 24 illustrates an exemplary embodiment of a smaller foam piece2400. The smaller foam piece 2400 is made by cutting a laminated foamboard 1300 or 1700. The laminated foam board 1300 or 1700 may be cut ina wide variety of different ways to make the smaller foam piece 2400.For example, a laminated foam board 1300 or 1700 may be cut with a hotwire or a saw blade, such as a band saw blade, a reciprocating sawblade, an abrasive wire or a circular saw blade to foul a plurality ofsmaller foam pieces. The smaller foam pieces 2400 are made in anappropriate size for making a foam part.

In one exemplary embodiment, a cut surface 2402 of the smaller foampiece 2400 is very smooth across the bond lines 2404. The thermalbonding processes and apparatus described above make this very smoothcut surface 2402 across the bond lines 2404 possible. The laminated foamboards 1300, 1700 are free of the cavities or voids 302 (See FIG. 3),channels 602 (See FIG. 6), and unexpected areas of harder/densermaterial 600 (See FIG. 6). The presence of only a consistently locateduniform bond line, without these defects, allows the very smooth cutsurface 2402 to be formed. The very smooth cut surface 2402 allows highquality foam parts, without surface imperfections to be made from thebillets 2400. In one exemplary embodiment, the flatness variation F3 ofthe smaller foam piece 2400 across a bond line is less than or equal to0.005 inches, such as less than 0.004 inches, such as less than 0.003inches.

The laminated foam board 1300, 1700 or the smaller foam piece 2400 canbe cut into foam parts 2900 (See FIG. 29) in a wide variety of differentways. In one exemplary embodiment, the smaller foam piece 2400 is cutinto a foam part 2900 with a rotary cutting tool 2500 (See FIGS. 25A and25B). The rotary cutting tool 2500 can take a wide variety of differentforms. In one exemplary embodiment, the rotary cutting tool 2500 is arouter-type tool with a head 2510 shaped to cut an appropriate shapeinto the smaller foam piece 2400 and a shaft 2512 for rotating the head.FIGS. 25A and 25B illustrate two examples of rotary cutting tools 2500for machining the billets 2400 into foam parts 2900. The cutting head2510 a illustrated by FIG. 25A cuts an external curved surface 2710 (SeeFIG. 27). The cutting head 2510 b cuts an internal curved surface 2910(See FIG. 29). FIGS. 26-29 illustrate the cutting heads 2510 a, 2510 bmachining the billet 2400 to form a part 2900. In the exampleillustrated by FIGS. 26-30, the foam part 2900 is one-half of acylindrical pipe insulation cover (the second half being a copy of thefirst). However, the smaller foam piece 2400 and cutting tools 2500 canbe configured and used to make a wide variety of different types of foamparts, such as elbows, T-shaped pipe covers, etc. Referring to FIGS. 26and 27, the cutting head 2510 a removes foam material along an edge 2610to provide the part with a first curved outer surface 2612, such as aradiused surface. In the example, the cutting head 2510 removes foammaterial and a portion of the material of the bond line 2404. Referringto FIGS. 26 and 28, the cutting head 2510 a removes foam material alongan edge 2614 to provide the part with a second curved outer surface2710, such as a radiused surface. In the example, the cutting head 2510removes foam material and a portion of the material of the bond line2404. Referring to FIGS. 26 and 29, the cutting head 2510 b removes foammaterial along a bottom surface 2618 to provide the part with a curvedinner surface 2622, such as a cylindrical inner surface. In the example,the cutting head 2510 b removes foam material and a portion of thematerial of the bond lines 2404. FIG. 30 illustrates the finished foampart 2900.

In one exemplary embodiment, a machined surface 2710, 2910 of the foampart 2900 is very smooth and uniform across the bond lines 2404. Thethermal bonding processes and apparatus described above make this verysmooth and uniform machined surface 2710, 2910 across the bond lines2404 possible. The laminated foam boards 1300, 1700 are free of thecavities or voids 302 (See FIG. 3), channels 602 (See FIG. 6), andunexpected areas of harder/denser material 600 (See FIG. 6). Thepresence of only a consistently located uniform bond line, without thesedefects, allows the very smooth and uniform machined surface 2710, 2910to be formed. The very smooth cut surface 2710, 2910 results in highquality foam parts 2900, without surface imperfections at the bondline(s) to be made. In one exemplary embodiment, the profile tolerancePT of the foam part 2700 across a bond line 2404 is less than or equalto 0.015 inches, such as less than 0.010 inches, such as less than 0.005inches. The profile tolerance PT is the difference between the intendedor designed shape and the actual shape of the part in the area of thebond line, such as the bond line and ¼ inch on each side of the bondline. For example, the intended shape of the outer surface of the part2900 illustrated by FIG. 30 may be a four inch diameter cylinder. Theprofile tolerance PT in the area of the bond line may be 0.010 inches.If a cavity or void 302 (See FIG. 3) or a channel 602 (See FIG. 6) witha remaining portion (i.e. the portion that remains after machining) thatis deeper than 0.010 inches were in the machined bond line 2404, thepart 2900 would be outside of the profile tolerance.

FIG. 31 illustrates an exemplary embodiment of a method of making a foamproduct 2900 and recycling the polystyrene foam to make new polystyreneboards 3100. In the embodiment illustrated by FIG. 31 a smaller foampiece 2400 is provided that is machined from one of the laminatedpolystyrene boards 1300, 1700 described herein. Since the laminatedpolystyrene boards 1300, 1700 are made only from the polystyrenematerial of the boards, the smaller foam pieces also only includepolystyrene. The billet 2400 is machined to remove a portion 3102 of theextruded polystyrene to form the foam product 2900. For example, thebillet 2400 may be machined as illustrated by the embodiment of FIGS.26-29. The removed polystyrene material 3102 is recycled to make anotherpolystyrene product. For example, the polystyrene material 3102 may berecycled to make a new polystyrene board or be mixed with virginpolystyrene material that is used to make a new polystyrene board 3100.

FIG. 38 illustrates an exemplary embodiment of a rotary cutting tool2500 for shaping foam products, such as the foam product 2900illustrated by FIG. 30. The rotary foam cutting tool 2500 can be used tocut a wide variety of different foams including, but not limited to,single layer foam boards or pieces and multilayer foam boards andpieces. The rotary cutting tool can cut multilayer foam boards or piecesthat are thermally laminated together and/or that are bonded togetherwith an adhesive. The illustrated rotary cutting tool 2500 includes anannular support 3802 made from sheetmetal, such as aluminum or steel,and cutting elements 3804 secured to the annular sheetmetal support3802. A base 3820 is secured to the sheetmetal annular support 3802 forrotating the sheetmetal annular support 3802 and attached cuttingelements 3804.

The annular sheetmetal support 3802 can be made in a wide variety ofdifferent ways. For example, the sheetmetal support can be made byspin-forming, stamping, drawing, deep drawing, or any other conventionalsheetmetal forming technique. FIGS. 32 and 33 illustrate that theannular support 3802 can be formed from a flat, circular sheetmetal disk3200. The sheetmetal disk 3200 can be formed into the annular support3802 shape illustrated by FIG. 34 by spin-forming, stamping, drawing,deep drawing, or any other conventional sheetmetal forming technique.

The cutting elements 3804 can be secured to the annular sheetmetalsupport 3802 in a wide variety of different ways. For example, thecutting elements 3804 can be secured to the annular sheetmetal support3802 by brazing, welding, with an adhesive or any other conventionaladhesion technique. The cutting elements can take a wide variety ofdifferent forms. In one exemplary embodiment, the cutting elements 3804are made from a material that wears very slowly when cutting polystyrenefoam, such as carbide, hardened steel, ceramics and other hardmaterials. In one exemplary embodiment, the cutting elements 3804 arespaced apart a sufficient distance that prevents the build up andretention of the polystyrene foam. This prevention of the accumulationof the foam material on the tool reduces friction between the tool andthe part, which improves the life expectancy of the tool and providesfor a cleaner cut on the thermoplastic material. Referring to FIGS. 36and 37, in one exemplary embodiment the cutting elements 3804 areinitially provided on a tape 3600, such as a brazing tape or an adhesivetape. The tape 3600 is provided over the cutting surface 3602 of thesheetmetal support 3802 and then processed to permanently secure thecutting elements 3804 to the sheetmetal support 3802. For example thetape 3600 may be heated to braze the cutting elements 3804 to thesheetmetal support 3802 or cure an adhesive of the tape to secure thecutting elements to the sheetmetal support.

The base 3820 can take a wide variety of different forms. In theillustrates embodiment, the base 3820 includes a circular plate 3830.However, the base can comprise any structure for supporting and rotatingthe sheetmetal support 3802. The resulting cutting tool 2500 is hollowand lightweight. This hollow and lightweight configuration allows foammachining tools to be made in sizes that were not previously possible.The following table, with columns corresponding to the dimensions onFIG. 38, provides examples of cutting tools 3800 with the hollow andlight weight configuration. Each row provides a different example. Alldimensions in the following table are in inches. As can be seen from thechart and FIG. 34, tools 3800 having diameters A over 5 inches, over 10inches, over 15 inches and over 20 inches can be made with the hollowsheetmetal design.

“A” “B” “C” “D” “E” 5.76 1.44 0.25 0.63 0.50 6.38 1.75 0.25 0.63 0.506.88 2.00 0.25 0.63 0.50 7.38 2.25 0.25 0.63 0.50 7.88 2.50 0.25 0.630.50 8.44 2.78 0.25 0.63 0.50 9.5 3.31 0.25 0.63 0.50 10.5 3.81 0.250.63 0.50 11.5 4.31 0.25 0.63 0.50 12.5 4.81 0.25 0.63 0.50 13.63 5.380.25 0.63 0.50

The present application discloses several different embodiments ofthermally laminated foam boards, methods for making thermally laminatedfoam boards, apparatus for making thermally laminated foam boards,smaller foam pieces made from thermally laminated foam boards, methodsfor making smaller foam pieces from thermally laminated foam boards,parts made from thermally laminated foam boards, methods for makingparts from thermally laminated foam boards, and tools for making partsfrom thermally laminated foam boards. Any of the features of any of theembodiments disclosed in this application can be combined with any ofthe features of any of the other embodiments disclosed by thisapplication. Additional exemplary embodiments of the present applicationcomprise combinations and subcombinations of the features of theexemplary embodiments described above.

While the present invention has been illustrated by the description ofembodiments thereof, and while the embodiments have been described inconsiderable detail, it is not the intention of the applicants torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. Therefore, the invention, in its broaderaspects, is not limited to the specific details, the representativeapparatus, and illustrative examples shown and described. Accordingly,departures may be made from such details without departing from thespirit or scope of the applicant's general inventive concept.

1. A method of making a foam product comprising: thermally bonding atleast two polystyrene boards together two make a thick laminated board;machining the thick laminated board to remove a portion of thepolystyrene and thereby form the foam product; recycling the removedportion.
 2. The method of claim 1 wherein the removed portion isrecycled to make polystyrene boards.
 3. The method of claim 1 whereinthe thick laminated board consists of material of the at least twopolystyrene boards.
 4. The method of claim 1 wherein the removed portionconsists of material of the at least two polystyrene boards.
 5. Themethod of claim 1 wherein prior to said thermal bonding of the at leasttwo polystyrene boards together a flatness variation of face surfacesthat are bonded together is greater than 0.020 inches.
 6. The method ofclaim 5 wherein the flatness variation is measured across the facesurfaces of a two foot by two foot sample of polystyrene boards. 7.(canceled)
 8. The method of claim 5 further comprising flattening theface surfaces that are to be bonded together to a flatness variation ofless than 0.020 inches.
 9. The method of claim 1 further comprisingflattening face surfaces that are to be bonded together by a factor ofat least two.
 10. The method of claim 9 wherein said flatteningcomprises heating and applying pressure to the face surfaces withrollers.
 11. The method of claim 10 further comprising heating the facesurfaces with heating elements that are positioned between and spacedapart from the face surfaces downstream of the rollers.
 12. The methodof claim 1 wherein a flatness variation where the thick laminated boardis cut across a bond line between polystyrene boards is less than orequal to 0.005 inches from one side of the bond line to the other.
 13. Afoam product comprising: at least two polystyrene boards bonded togethertwo make a thick laminated board; wherein a portion of the polystyreneboard is removed to form a shape of the foam product; wherein the formedfoam product consists of material of the polystyrene boards.
 14. Thefoam product of claim 13 wherein the removed portion consists ofmaterial of the polystyrene boards.
 15. The foam product of claim 13wherein a bond area between each of the polystyrene boards issubstantially planar and has a bond thickness variation of less than0.020 inches.
 16. The foam product of claim 13 wherein a flatnessvariation where the thick laminated board is cut across a bond linebetween polystyrene boards are bonded together is less than or equal to0.005 inches from one side of the bond line to the other.
 17. A methodof making a foam product comprising: applying heat and pressure tofacing surfaces of a pair of opposed polystyrene boards to flatten thefacing surfaces by a factor of at least 2; thermally bonding at leastsaid pair of polystyrene boards together two make a thick laminatedboard; and machining the thick laminated board to remove a portion ofthe polystyrene and thereby form the foam product.
 18. The method ofclaim 17 wherein prior to said applying heat and pressure a flatnessvariation of said facing surfaces is greater than 0.020 inches.
 19. Themethod of claim 18 wherein the flatness is measured across the facesurfaces of a two foot by two foot samples of polystyrene boards. 20.(canceled)
 21. The method of claim 18 further comprising flattening theface surfaces that are to be bonded together to a flatness of less than0.020 inches.
 22. The method of claim 9 wherein said applying heat andpressure is by heated rollers.
 23. The method of claim 22 furthercomprising heating the face surfaces with heating elements that arepositioned between and spaced apart from the face surfaces downstream ofthe rollers.
 24. The method of claim 17 wherein a flatness variationwhere the thick laminated board is cut across a bond line betweenpolystyrene boards is less than or equal to 0.005 inches.
 25. Alaminated foam board comprising: first and second polystyrene boardseach having an outer skin that is formed during extrusion of thepolystyrene boards; wherein the polystyrene boards are laminatedtogether without removing the outer skin of faces that are bondedtogether; wherein a bond area between each of the polystyrene boards issubstantially planar and has a bond thickness variation of less than0.020 inches.
 26. A method of making a foam product comprising:thermally bonding at least two polystyrene boards together two make athick laminated board; cutting the thick laminated board into smallerfoam pieces: machining the smaller foam pieces to remove a portion ofthe polystyrene and thereby form the foam product; wherein a profiletolerance where the smaller foam piece is machined across a thermal bondline between polystyrene boards is less than or equal to 0.015 inchesfrom one side of the bond line to the other.
 27. The method of claim 26wherein prior to said thermal bonding of the at least two polystyreneboards together flatness of face surfaces that are bonded together aregreater than 0.020 inches.
 28. The method of claim 27 further comprisingflattening the face surfaces that are to be bonded together to aflatness of less than 0.020 inches.
 29. The method of claim 28 whereinsaid flattening comprises heating and applying pressure to the facesurfaces with rollers.
 30. The method of claim 29 further comprisingheating the face surfaces with heating elements that are positionedbetween and spaced apart from the face surfaces downstream of therollers.
 31. A foam product comprising: at least two polystyrene boardsthermally bonded together two make a thick laminated board; wherein aportion of the polystyrene board is removed across a bond line where twopolystyrene boards are thermally bonded together to form a shape of thefoam product; wherein a profile tolerance where the smaller foam pieceis machined across a thermal bond line between polystyrene boards isless than or equal to 0.015 inches from one side of the bond line to theother.
 32. The foam product of claim 31 wherein a bond area between eachof the polystyrene boards is substantially planar and has a bondthickness variation of less than 0.020.
 33. (canceled)